High-level Data Link Control (HDLC) is a general purpose data link control protocol. HDLC is a bit-oriented synchronous data link layer that uses synchronous digital signals for communication. The data is organized into units called frames and is sent to specified destinations.
HDLC is used for point-to-point and multipoint data links in telecommunication and computer networks. Often, HDLC devices are connected to each other by digital buses. HDLC manages the pace at which data is transmitted on a synchronous digital bus or other synchronous digital link.